slaves might be transported (the Act would be renewed several times before being made permanent in 1799). In 1792 the House of Commons voted in favour of "gradual" abolition, and in 1807 parliament outlawed the African slave trade by legislation. This prevented British merchants exporting any more people from Africa, but it did not alter the status of the several million existing slaves, and the courts continued to recognise colonial slavery. The abolitionists therefore turned their attention to the emancipation of West Indian slaves. Legally, this was difficult to achieve, since it required the compulsory divesting of private property; but it was finally done in 1833, at a cost of £20 million paid from public funds to compulsorily purchase slaves from their owners and then manumit them. Freed slaves themselves received no compensation for their forced labour. From 1 August 1834, all slaves in the British colonies were "absolutely and forever manumitted." In British colonies, it was widely assumed that positive law was needed to make slavery lawful, and various royal colonies passed laws to this effect. See also Abolitionism in the United Kingdom Colliers and Salters (Scotland) Act 1775 History of slavery Joseph Knight (slave) Slavery Abolition Act 1833 Slavery in international law Slavery in the colonial United States Slave Trade Acts, with a listing of international, UK and US slavery laws Slave Trade Act 1807 Slavery in Britain Slavery in Ireland Somersett's case Notes External links Slavery in England and the law M. Kaufmann, 'English Common Law, Slavery and', Encyclopaedia of Blacks in European History and Culture (2008),Vol. I, pp. 200-203) Slavery law Abolitionism in the United Kingdom Legal history of England Common law